This invention relates generally to containers for hazardous substances and, more particularly, to methods and apparatus for storing and shipping small quantities of hazardous materials for testing purposes.
The shipment of hazardous materials is strictly regulated by several National and International organizations. For example, both the International Air Transportation Association (IATA) and U.S. Department of Transportation (DOT) regulate the shipment of "dangerous goods." Under Section 2.7 of the IATA regulations and under 49 C.F.R. 173.4 and HM 181 of the DOT regulations, certain exceptions are made to the otherwise extremely stringent requirements for the shipment of dangerous goods. These exceptions are generally referred to as "Dangerous Goods In Excepted Quantities," or "Exceptions for Small Quantities."
In order to qualify for shipment under "Dangerous Goods In Excepted Quantities," the general rule is that no more than 30 mL of a hazardous liquid or 30 grams of a hazardous solid (such as oxidizers or corrosives) can be shipped within a single bottle. In addition, any container (e.g. box) enclosing the bottle holding the hazardous material must meet a number of Federally mandated tests including a drop test, a stack test, an internal pressure test, a Cobb water absorption test, and a vibration test. If the entire containment assembly passes these tests, it meets the aforementioned requirements and can be shipped by passenger or cargo aircraft. In addition, since regulations for air transport are more stringent than for ground transport, compliance with these air regulations ensures compliance with applicable ground transport regulations as well.
The purpose of the drop test is to access the package's ability to withstand mechanical hazards that occur in distribution, as specified in applicable United Nations and U.S. Department of Transportation Hazardous Materials (dangerous goods) documents. The requirements for this test can be found in USDOT 49 C.F.R., Subpart M, paragraph 178.603, UN Recommendations on the Transport of Dangerous Goods-9.73 IATA Dangerous Goods Regulations-10.3.3, ICAO Technical Instruction for the Safe Transport of Dangerous Goods by Air-Section 7, Chapter 4.3., incorporated herein by reference.
The purpose of the stack test is to determine the ability of the package to withstand a force applied to its top surface equivalent to the total combined weight of identical packages stacked on top of it during distribution. The height requirement for the stack test is a minimum of 3 meters (approximately 10 feet) including the test sample. The duration of the stack test is 24 hours.
In order to pass the stack test, the test sample must not leak. In composite packaging or combination packaging, there must be no leakage of the filling substance from the inner receptacle or the inner packaging. No test sample must show any deterioration which would adversely affect transport safety or any distortion liable to reduce its strength or to cause instability in stacks of packages. The regulations referring to the stacking test can be found in 47 C.F.R. Subpart M, paragraph 178.606, UN Recommendations on the Transport of Dangerous Goods-9.7.6, IATA Dangerous Goods Regulations-10.3.6, ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air-Section 7, Chapter 4.6., incorporated herein by reference.
The internal pressure test must be performed on metal, plastic, and composite packaging intended to contain liquids. Except for air transport, this test is not required for inner packaging of combination packaging. The appropriate regulations include USDOT 49 C.F.R. Subpart M, paragraph 178.605, UN Recommendations on the Transport of Dangerous Goods-9.7.5, IATA Dangerous Goods Regulations-10.3.5, and ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air-Section 7, Chapter 4.5., incorporated herein by reference.
The purpose of the water absorption test (referred to as the "Cobb" water absorption test) is to determine the quantity of water absorbed by non-bibulous paper and paper board in a specified amount of time under standardized conditions. This test is applied primarily to the outer packaging material. The appropriate regulations include USDOT subpart L, paragraph 178.516, UN Recommendations of the Transport of Dangerous Goods-9.6.11, IATA Dangerous Goods Regulations-10.2.1, ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air-Section 7, Chapter 3.1.10, and ISO International Standard 535-1976(E) 178.516(b)(1), incorporated herein by reference.
Each package must be capable of withstanding, without rupture of leakage, the vibration test. The packages are constrained horizontally and are left free to move vertically, to bounce, and to rotate. The packaging is then vibrated for about an hour. Immediately following the period of vibration, each package is removed from the platform, turn on its side, and observe for any evidence of leakage. A packaging passes the vibration test if there is no rupture of leakage from any of the packages. The appropriate regulation is 49 C.F.R., subpart M, paragraph 178.608, incorporated herein by reference.
It will therefore be appreciated that even when shipping dangerous goods in "Excepted Quantities," there are a number of stringent regulatory requirements that must be met. In the past, these conditions have been met by shipping such materials in a standard "4G" package designed and certified for use in shipping much larger quantities (e.g. 250 mL to 1 L). The 4G box is over-designed for "Dangerous Goods in Excepted Quantities" and, therefore, is larger, more cumbersome, more ill-fitting, and more expensive than necessary. A typical 4G package includes a container for the sample that is packed along with a loose, absorbent material (e.g. Vermiculite) inside of a metal can, which is then packed within a fiberboard box of specified characteristics. The smallest typical 4G package to hold a single sample is 9 inches by 5 inches by 5 inches.
Another disadvantage of shipping hazardous materials in standard 4G boxes is that it requires special documentation to be completed before air transportation carriers will accept the boxes for transport. This documentation is specified under IATA regulations entitled "Shipper's Declaration of Hazardous Materials." All commercial transportation services require a significant surcharge for processing this special documentation.
An additional drawback with most of the prior art 4G packages is that the absorbent material is loosely packed in the container and can settle during transport, creating only a partial protection in case of leakage. Furthermore, many 4G packages rely on the absorbent material, such as the aforementioned Vermiculite, for their cushioning properties. Unfortunately, as the absorbent material settles and packs, the cushioning properties of the material are reduced.